Intel Management Engine
. The ME is colloquially categorized as ring −3, below (ring −2) and the (ring −1), all running at a higher privilege level than the kernel (ring 0)}} s since 2008. It is located in the of modern Intel .}} It is a part of , which allows system administrators to perform tasks on the machine remotely. System administrators can use it to turn the computer on and off, and they can login remotely into the computer regardless of whether or not an operating system is installed. The Intel Management Engine always runs as long as the motherboard is receiving power, even when the computer is turned off. Intel has not released much information on the Intel Management Engine, prompting speculation that it may include a . The has voiced concern about IME. processors have a similar feature, called . Design The subsystem primarily consists of proprietary firmware running on a separate microprocessor that performs tasks during boot-up, while the computer is running, and while it is asleep. is connected to current (via battery or power supply), it continues to run even when the system is turned off.}} Intel claims the ME is required to provide full performance. Its exact workings are largely undocumented and its code is using confidential stored directly in hardware, so the firmware does not contain the information necessary to decode its contents. Intel's main competitor AMD has incorporated the equivalent (formally called Platform Security Processor) in virtually all of its post-2013 CPUs. Hardware x86-based CPU and runs the MINIX 3 operating system.}} The ME state is stored in a partition of the , using the (EFFS). Previous versions were based on an , with the Management Engine running the . Versions 1.x to 5.x of the ME used the ARCTangent-A4 (32-bit only instructions) whereas versions 6.x to 8.x used the newer ARCompact (mixed 32- and ). Starting with ME 7.1, the ARC processor could also execute signed . for what support exists in various Ethernet controllers, exported and made configurable via (MCTP). The ME also communicates with the host via PCI interface. Under Linux, communication between the host and the ME is done via /dev/mei. Until the release of processors, the ME was usually embedded into the motherboard's , following the (MCH) layout. With the newer Intel architectures ( onwards), ME is included into the (PCH). Firmware By Intel's current terminology as of 2017, ME is one of several firmware sets for the Converged Security and Manageability Engine (CSME). Prior to AMT version 11, CSME was called Intel Management Engine BIOS Extension (Intel MEBx). * Management Engine (ME) – mainstream chipsets * Server Platform Services (SPS) – server chipsets and s * Trusted Execution Engine (TXE) – tablet/embedded/low power The Russian company Positive Technologies ( ) found that the ME firmware version 11 runs . Modules * (AMT) * (ASF) support * Intel (IBG) and * Integrated Clock Controller (ICC) * (QST), formerly known as Advanced Fan Speed Control (AFSC), which provides support for acoustically-optimized fan speed control, and monitoring of temperature, voltage, current and fan speed sensors that are provided in the chipset, CPU and other devices present on the motherboard. Communication with the QST firmware subsystem is documented and available through the official (SDK). * Protected Audio Video Path (used in DRM) * Intel Security Assist (ISA) * (SOL) * Firmware-based (TPM) Security vulnerabilities On May 1, 2017, Intel confirmed a Remote Elevation of Privilege bug (SA-00075) in its Management Technology. Every Intel platform with provisioned Intel Standard Manageability, Active Management Technology, or Small Business Technology, from in 2008 to in 2017 has a remotely exploitable security hole in the ME. Several ways to disable the ME without authorization that could allow ME's functions to be sabotaged have been found. Additional major security flaws in the ME affecting a very large number of computers incorporating ME, Trusted Execution Engine (TXE), and Server Platform Services (SPS) firmware, from in 2015 to in 2017, were confirmed by Intel on 20 November 2017 (SA-00086). Unlike SA-00075, this bug is even present if AMT is absent, not provisioned or if the ME was "disabled" by any of the known unofficial methods. In July 2018 another set of vulnerabilitites were disclosed (SA-00112). In September 2018, yet another vulnerability was published (SA-00125). Ring −3 rootkit A −3 rootkit was demonstrated by Invisible Things Lab for the Q35 chipset; it does not work for the later Q45 chipset as Intel implemented additional protections. The exploit worked by remapping the normally protected memory region (top 16 MB of RAM) reserved for the ME. The ME rootkit could be installed regardless of whether the AMT is present or enabled on the system, as the chipset always contains the ARC ME coprocessor. (The "−3" designation was chosen because the ME coprocessor works even when the system is in the , thus it was considered a layer below the rootkits.) For the vulnerable Q35 chipset, a ME-based rootkit was demonstrated by Patrick Stewin. Zero-touch provisioning Another security evaluation by Vassilios Ververis showed serious weaknesses in the GM45 chipset implementation. In particular, it criticized AMT for transmitting unencrypted passwords in the SMB provisioning mode when the IDE redirection and Serial over LAN features are used. It also found that the "zero touch" provisioning mode (ZTC) is still enabled even when the AMT appears to be disabled in BIOS. For about 60 euros, Ververis purchased from a certificate that is accepted by the ME firmware and allows remote "zero touch" provisioning of (possibly unsuspecting) machines, which broadcast their HELLO packets to would-be configuration servers. SA-00075 (aka Silent Bob is Silent) In May 2017, Intel confirmed that many computers with AMT have had an unpatched critical privilege escalation vulnerability ( ). The vulnerability, which was nicknamed "Silent Bob is Silent" by the researchers who had reported it to Intel, affects numerous laptops, desktops and servers sold by , , (later and ), Intel, , and possibly others. Those researchers claimed that the bug affects systems made in 2010 or later. Other reports claimed the bug also affects systems made as long ago as 2008. The vulnerability was described as giving remote attackers: PLATINUM In June 2017, the cybercrime group became notable for exploiting the capabilities of AMT to perform data exfiltration of stolen documents. SA-00086 Some months after the previous bugs, and subsequent warnings from the EFF, security firm Positive Technologies claimed to have developed a working . On 20 November, 2017 Intel confirmed that a number of serious flaws had been found in the Management Engine (mainstream), Trusted Execution Engine (tablet/mobile), and Server Platform Services (high end server) firmware, and released a "critical firmware update". Essentially every Intel-based computer for the last several years, including most desktops and servers, were found to be vulnerable to having their security compromised, although all the potential routes of exploitation were not entirely known. It is not possible to patch the problems from the operating system, and a firmware (UEFI, BIOS) update to the motherboard is required, which was anticipated to take quite some time for the many individual manufacturers to accomplish, if it ever would be for many systems. Affected systems * – C3000 family * Intel Atom – Apollo Lake E3900 series * – N and J series * (i3, i5, i7, i9) – 1st, 2nd, 3rd, 4th, 5th, 6th, 7th, and 8th generation * – Apollo Lake * – E3-1200 v5 and v6 product family * Intel Xeon – Scalable family * Intel Xeon – W family Mitigation None of the known unofficial methods to disable the ME prevent exploitation of the vulnerability. A firmware update by the vendor is required. However, those who discovered the vulnerability note that firmware updates are not fully effective either, as an attacker with access to the ME firmware region can simply flash an old, vulnerable version and then exploit the bug. SA-00112 In July 2018 Intel announced that 3 vulnerabilities (CVE-2018-3628, CVE-2018-3629 and CVE-2018-3632) had been discovered and that a patch for the CSME firmware would be required. Intel indicated there would be no patch for 3rd generation Core processors or earlier despite chips or their chipsets as far back as Intel Core 2 Duo vPro and Intel Centrino 2 vPro being affected. Disabling the ME Some undocumented methods to do so were discovered, however. These methods are not supported by Intel. The ME's security architecture is designed to prevent disabling, and thus its possibility is considered by Intel to be a security vulnerability. For example, a virus could abuse it to make the computer lose some of the functionality that the typical end-user expects, such as the ability to play media with . On the other hand, a malicious actor could use the ME to remotely compromise a system. Strictly speaking, none of the known methods disables the ME completely, since it is required for booting the main CPU. All known methods merely make the ME go into abnormal states soon after boot, in which it seems not to have any working functionality. The ME is still physically connected to the current and its microprocessor is continuing to execute code. Undocumented methods Firmware neutering In 2016, the me_cleaner project found that the ME's integrity verification is broken. The ME is supposed to detect that it has been tampered with, and, if this is the case, shut down the PC forcibly after every 30 minutes after system start. This prevents a compromised system from running undetected, yet allows the owner to fix the issue by flashing a valid version of the ME firmware during the grace period. As the project found out, by making unauthorized changes to the ME firmware, it was possible to force it into an abnormal error state that prevented triggering the shutdown even if large parts of the firmware had been overwritten and thus made inoperable. "High Assurance Platform" mode In August 2017, Russian company Positive Technologies ( ) published a method to disable the ME via an . As to make the ME go into High-Assurance Platform (HAP) mode after boot. This mode disables most of ME's functions, and was intended to be available only in machines produced for specific purchasers like the US government;}} however, most machines sold on the retail market can be made to activate the switch. Manipulation of the HAP bit was quickly incorporated into the me_cleaner project. Commercial ME disablement * previously petitioned Intel to sell processors without the ME, or release its source code, calling it "a threat to users' digital rights". In March 2017, Purism announced that it had neutralized the ME by erasing the majority of the ME code from the flash memory. It further announced in October 2017 that new batches of their -based Librem line of laptops will ship with the ME neutralized (via erasing the majority of ME code from the flash, as previously announced), and additionally disabling most ME operation via the HAP bit. Updates for existing Librem laptops were also announced. * announced in November 2017 their plan to disable the ME on their new and recent -based machines via the HAP bit. * , in December 2017, began showing certain laptops on its website that offered the "Systems Management" option "Intel vPro - ME Inoperable, Custom Order" for an additional fee. Dell has not announced or publicly explained the methods used. In response to press requests, Dell stated that those systems had been offered for quite a while, but not for the general public, and had found their way to the website only inadvertently. The laptops are available only by custom order and only to military, government and intelligence agencies. They are specifically designed for covert operations, such as providing a very robust case and a "stealth" operating mode kill switch that disables display, LED lights, speaker, fan and any wireless technology. Effectiveness against vulnerabilities None of the two methods to disable the ME discovered so far turned out to be an effective countermeasure against the SA-00086 vulnerability. This is because the vulnerability is in an early-loaded ME module that is essential to boot the main CPU. Claims that ME is a backdoor (EFF) and security expert Damien Zammit accused the ME of being a and a privacy concern.}} Zammit stresses that the ME has full access to memory (without the parent CPU having any knowledge); has full access to the TCP/IP stack and can send and receive network packets independently of the operating system, thus bypassing its firewall. Intel responded by saying that "Intel does not put back doors in its products nor do our products give Intel control or access to computing systems without the explicit permission of the end user." and "Intel does not and will not design backdoors for access into its products. Recent reports claiming otherwise are misinformed and blatantly false. Intel does not participate in any efforts to decrease security of its technology." In the context of criticism of the Intel ME and and it has been conjectured that Intel ME and AMD Secure Technology might be part of that programme. Reactions , Google was attempting to eliminate firmware from its servers and found that the ME was a hurdle to that. Reaction by AMD processor vendors Shortly after SA-00086 was patched, vendors for AMD processor mainboards started shipping BIOS updates that allow disabling the , a subsystem with similar function as the ME. Relationship between IME and Intel Active Management Technology . AMT runs on the ME, but is only available on processors with . AMT enables owners remote administration of their computer, like turning it on or off and reinstalling the operating system.}} However, the ME itself is built into all Intel chipsets since 2008, not only those with AMT. While AMT can be unprovisioned by the owner, there is no official, documented way to disable the ME. References Category:Computer science